Check your tire pressure when the tires are cold, and use the number on the sticker inside your driver's door, not the number on the tire. In Arizona, hot pavement and summer air raise tire pressure fast, so a reading after a drive can look much higher than it really is. A reading takes about five minutes with a basic gauge.
Time: about 5 minutes. Skill: easy.
What does cold mean?
Cold means the car has been parked for at least three hours, or driven only a short distance, like a mile. In summer, aim for early morning, before the sun heats the pavement, or a shaded garage. A tire that has been driven on hot asphalt can read several pounds per square inch (psi) higher than its cold pressure.
What do you need?
- A tire pressure gauge (digital or dial)
- An air source: a home compressor, a portable pump, or an air machine at a station
- A coin for checking tread
How do you check tire pressure?
- Find the right number. Open the driver's door and look at the sticker on the door jamb. It lists the recommended cold pressure for the front and rear tires. Your owner's manual has it too. Do not use the number molded into the tire's sidewall. That is the tire's maximum, not what your car needs.
- Unscrew the valve cap on one tire and keep it in your pocket.
- Press the gauge firmly onto the valve stem. You will hear a short hiss, then it stops. Read the number.
- Compare it to the sticker. If it is low, add air in short bursts and recheck. If it is high and the tires are cold, press the pin inside the valve with the gauge tip to let some air out.
- Replace the cap. Repeat for all four tires and check the spare if you have one.
What if the tires are already hot?
A hot tire reads higher. A common rule is that pressure changes by about 1 psi for every 10 degrees of temperature change. Do not let air out of hot tires to match the sticker, because they will be too low when they cool. If you must add air at a station after driving, add a little and recheck cold the next morning.
Why does my tire pressure light come on in the morning?
Pressure drops when the air gets cooler. The big swings between hot afternoons and cool nights, and the first cold mornings of the year, can turn on the warning light. Check all four tires with a gauge. If one tire is lower than the others or loses air every few days, you may have a slow leak.
How do you check tread?
Put a coin in the groove with the head upside down. If you can see the top of the head, the tread is shallow and it is time to replace. Look also for cracks in the sidewalls, bulges, nails or uneven wear. Arizona heat breaks down rubber, so older tires can crack even when the tread looks fine. The four-digit date code on the sidewall tells you the week and year the tire was made. Ask a tire shop how old is too old for your tires.
When to call a pro
Visit a tire shop if a tire keeps losing air, you see a nail, bulge or crack, the tread is low, or the car pulls to one side or shakes. Many shops check pressure and look at your tires quickly. Here are local tire shops in the directory, with phone numbers:
For other car trouble, ask the helper or browse Phoenix businesses.
Questions people ask
What should my tire pressure be?
Use the number on the sticker inside your driver's door or in your owner's manual. It is different from the maximum pressure printed on the tire.
Is it okay to check tire pressure in the afternoon in Arizona?
You can, but the reading will be higher than the cold pressure. For the most accurate result, check early morning before driving, or after the car has sat in the shade for a few hours.
How often should I check my tire pressure?
At least once a month, and before a long road trip. Check more often when temperatures swing between seasons.
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